// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef UI_VIEWS_WIDGET_DESKTOP_AURA_X11_DESKTOP_HANDLER_H_
#define UI_VIEWS_WIDGET_DESKTOP_AURA_X11_DESKTOP_HANDLER_H_

#include <X11/Xlib.h>
#include <stdint.h>
// Get rid of a macro from Xlib.h that conflicts with Aura's RootWindow class.
#undef RootWindow

#include <vector>

#include "base/macros.h"
#include "ui/aura/env_observer.h"
#include "ui/events/platform/platform_event_dispatcher.h"
#include "ui/gfx/x/x11_atom_cache.h"
#include "ui/gfx/x/x11_types.h"
#include "ui/views/views_export.h"

namespace base {
template <typename T>
struct DefaultSingletonTraits;
}

namespace views {

// A singleton that owns global objects related to the desktop and listens for
// X11 events on the X11 root window. Destroys itself when aura::Env is
// deleted.
class VIEWS_EXPORT X11DesktopHandler : public ui::PlatformEventDispatcher,
                                       public aura::EnvObserver {
public:
    // Returns the singleton handler.
    static X11DesktopHandler* get();

    // Gets/sets the X11 server time of the most recent mouse click, touch or
    // key press on a Chrome window.
    int wm_user_time_ms() const
    {
        return wm_user_time_ms_;
    }
    void set_wm_user_time_ms(unsigned long time_ms)
    {
        wm_user_time_ms_ = time_ms;
    }

    // Sends a request to the window manager to activate |window|.
    // This method should only be called if the window is already mapped.
    void ActivateWindow(::Window window);

    // Attempts to get the window manager to deactivate |window| by moving it to
    // the bottom of the stack. Regardless of whether |window| was actually
    // deactivated, sets the window as inactive in our internal state.
    void DeactivateWindow(::Window window);

    // Checks if the current active window is |window|.
    bool IsActiveWindow(::Window window) const;

    // Processes activation/focus related events. Some of these events are
    // dispatched to the X11 window dispatcher, and not to the X11 root-window
    // dispatcher. The window dispatcher sends these events to here.
    void ProcessXEvent(XEvent* event);

    // ui::PlatformEventDispatcher
    bool CanDispatchEvent(const ui::PlatformEvent& event) override;
    uint32_t DispatchEvent(const ui::PlatformEvent& event) override;

    // Overridden from aura::EnvObserver:
    void OnWindowInitialized(aura::Window* window) override;
    void OnWillDestroyEnv() override;

private:
    enum ActiveState {
        ACTIVE,
        NOT_ACTIVE
    };

    X11DesktopHandler();
    ~X11DesktopHandler() override;

    // Handles changes in activation.
    void OnActiveWindowChanged(::Window window, ActiveState active_state);

    // Called when |window| has been created or destroyed. |window| may not be
    // managed by Chrome.
    void OnWindowCreatedOrDestroyed(int event_type, XID window);

    // The display and the native X window hosting the root window.
    XDisplay* xdisplay_;

    // The native root window.
    ::Window x_root_window_;

    // The last known active X window
    ::Window x_active_window_;

    // The X11 server time of the most recent mouse click, touch, or key press
    // on a Chrome window.
    unsigned long wm_user_time_ms_;

    // The active window according to X11 server.
    ::Window current_window_;

    // Whether we should treat |current_window_| as active. In particular, we
    // pretend that a window is deactivated after a call to DeactivateWindow().
    ActiveState current_window_active_state_;

    ui::X11AtomCache atom_cache_;

    bool wm_supports_active_window_;

    DISALLOW_COPY_AND_ASSIGN(X11DesktopHandler);
};

} // namespace views

#endif // UI_VIEWS_WIDGET_DESKTOP_AURA_X11_DESKTOP_HANDLER_H_
